Palm Pistol Defensive Firearm

The Palm Pistol is an ergonomically innovative single shot double action only defensive firearm chambered in 9mm that may be fired using either hand without regard to orientation of the stock. Suited for home defense, concealed carry or as a backup gun. It is also ideal for seniors, disabled or others who may have limited strength or manual dexterity. Using the thumb instead of the index finger for firing, it significantly reduces muzzle drift, one of the principle causes of inaccurate targeting.

Isaac Asimov fans should have no difficulty in recognizing the needle-gun from Lucky Starr and the Moons of Jupiter:

This was another one of those times when Bigman was glad he carried a needle-gun even in the face of Lucky's disapproval... Bigman clenched his fist about the weapon (of which only half-inch of snout, narrowing to a needlepoint, showed between the second and third fingers of his right hand) and squeezed just tightly enough to activate it.
(Read more about Asimov's needle-gun)